/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/* globals VBArray, PDFJS */

'use strict';

// Initializing PDFJS global object here, it case if we need to change/disable
// some PDF.js features, e.g. range requests
if (typeof PDFJS === 'undefined') {
    (typeof window !== 'undefined' ? window : this).PDFJS = {};
}

// Checking if the typed arrays are supported
(function checkTypedArrayCompatibility() {
    if (typeof Uint8Array !== 'undefined') {
        // some mobile versions do not support subarray (e.g. safari 5 / iOS)
        if (typeof Uint8Array.prototype.subarray === 'undefined') {
            Uint8Array.prototype.subarray = function subarray(start, end) {
                return new Uint8Array(this.slice(start, end));
            };
            Float32Array.prototype.subarray = function subarray(start, end) {
                return new Float32Array(this.slice(start, end));
            };
        }

        // some mobile version might not support Float64Array
        if (typeof Float64Array === 'undefined')
            window.Float64Array = Float32Array;

        return;
    }

    function subarray(start, end) {
        return new TypedArray(this.slice(start, end));
    }

    function setArrayOffset(array, offset) {
        if (arguments.length < 2)
            offset = 0;
        for (var i = 0, n = array.length; i < n; ++i, ++offset)
            this[offset] = array[i] & 0xFF;
    }

    function TypedArray(arg1) {
        var result;
        if (typeof arg1 === 'number') {
            result = [];
            for (var i = 0; i < arg1; ++i)
                result[i] = 0;
        } else if ('slice' in arg1) {
            result = arg1.slice(0);
        } else {
            result = [];
            for (var i = 0, n = arg1.length; i < n; ++i) {
                result[i] = arg1[i];
            }
        }

        result.subarray = subarray;
        result.buffer = result;
        result.byteLength = result.length;
        result.set = setArrayOffset;

        if (typeof arg1 === 'object' && arg1.buffer)
            result.buffer = arg1.buffer;

        return result;
    }

    window.Uint8Array = TypedArray;

    // we don't need support for set, byteLength for 32-bit array
    // so we can use the TypedArray as well
    window.Uint32Array = TypedArray;
    window.Int32Array = TypedArray;
    window.Uint16Array = TypedArray;
    window.Float32Array = TypedArray;
    window.Float64Array = TypedArray;
})();

// URL = URL || webkitURL
(function normalizeURLObject() {
    if (!window.URL) {
        window.URL = window.webkitURL;
    }
})();

// Object.create() ?
(function checkObjectCreateCompatibility() {
    if (typeof Object.create !== 'undefined')
        return;

    Object.create = function objectCreate(proto) {
        function Constructor() {
        }

        Constructor.prototype = proto;
        return new Constructor();
    };
})();

// Object.defineProperty() ?
(function checkObjectDefinePropertyCompatibility() {
    if (typeof Object.defineProperty !== 'undefined') {
        var definePropertyPossible = true;
        try {
            // some browsers (e.g. safari) cannot use defineProperty() on DOM objects
            // and thus the native version is not sufficient
            Object.defineProperty(new Image(), 'id', { value: 'test' });
            // ... another test for android gb browser for non-DOM objects
            var Test = function Test() {
            };
            Test.prototype = { get id() {
            } };
            Object.defineProperty(new Test(), 'id',
                { value: '', configurable: true, enumerable: true, writable: false });
        } catch (e) {
            definePropertyPossible = false;
        }
        if (definePropertyPossible) return;
    }

    Object.defineProperty = function objectDefineProperty(obj, name, def) {
        delete obj[name];
        if ('get' in def)
            obj.__defineGetter__(name, def['get']);
        if ('set' in def)
            obj.__defineSetter__(name, def['set']);
        if ('value' in def) {
            obj.__defineSetter__(name, function objectDefinePropertySetter(value) {
                this.__defineGetter__(name, function objectDefinePropertyGetter() {
                    return value;
                });
                return value;
            });
            obj[name] = def.value;
        }
    };
})();

// Object.keys() ?
(function checkObjectKeysCompatibility() {
    if (typeof Object.keys !== 'undefined')
        return;

    Object.keys = function objectKeys(obj) {
        var result = [];
        for (var i in obj) {
            if (obj.hasOwnProperty(i))
                result.push(i);
        }
        return result;
    };
})();

// No readAsArrayBuffer ?
(function checkFileReaderReadAsArrayBuffer() {
    if (typeof FileReader === 'undefined')
        return; // FileReader is not implemented
    var frPrototype = FileReader.prototype;
    // Older versions of Firefox might not have readAsArrayBuffer
    if ('readAsArrayBuffer' in frPrototype)
        return; // readAsArrayBuffer is implemented
    Object.defineProperty(frPrototype, 'readAsArrayBuffer', {
        value: function fileReaderReadAsArrayBuffer(blob) {
            var fileReader = new FileReader();
            var originalReader = this;
            fileReader.onload = function fileReaderOnload(evt) {
                var data = evt.target.result;
                var buffer = new ArrayBuffer(data.length);
                var uint8Array = new Uint8Array(buffer);

                for (var i = 0, ii = data.length; i < ii; i++)
                    uint8Array[i] = data.charCodeAt(i);

                Object.defineProperty(originalReader, 'result', {
                    value: buffer,
                    enumerable: true,
                    writable: false,
                    configurable: true
                });

                var event = document.createEvent('HTMLEvents');
                event.initEvent('load', false, false);
                originalReader.dispatchEvent(event);
            };
            fileReader.readAsBinaryString(blob);
        }
    });
})();

// No XMLHttpRequest.response ?
(function checkXMLHttpRequestResponseCompatibility() {
    var xhrPrototype = XMLHttpRequest.prototype;
    if (!('overrideMimeType' in xhrPrototype)) {
        // IE10 might have response, but not overrideMimeType
        Object.defineProperty(xhrPrototype, 'overrideMimeType', {
            value: function xmlHttpRequestOverrideMimeType(mimeType) {
            }
        });
    }
    if ('response' in xhrPrototype ||
        'mozResponseArrayBuffer' in xhrPrototype ||
        'mozResponse' in xhrPrototype ||
        'responseArrayBuffer' in xhrPrototype)
        return;
    // IE9 ?
    if (typeof VBArray !== 'undefined') {
        Object.defineProperty(xhrPrototype, 'response', {
            get: function xmlHttpRequestResponseGet() {
                return new Uint8Array(new VBArray(this.responseBody).toArray());
            }
        });
        return;
    }

    // other browsers
    function responseTypeSetter() {
        // will be only called to set "arraybuffer"
        this.overrideMimeType('text/plain; charset=x-user-defined');
    }

    if (typeof xhrPrototype.overrideMimeType === 'function') {
        Object.defineProperty(xhrPrototype, 'responseType',
            { set: responseTypeSetter });
    }
    function responseGetter() {
        var text = this.responseText;
        var i, n = text.length;
        var result = new Uint8Array(n);
        for (i = 0; i < n; ++i)
            result[i] = text.charCodeAt(i) & 0xFF;
        return result;
    }

    Object.defineProperty(xhrPrototype, 'response', { get: responseGetter });
})();

// window.btoa (base64 encode function) ?
(function checkWindowBtoaCompatibility() {
    if ('btoa' in window)
        return;

    var digits =
        'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

    window.btoa = function windowBtoa(chars) {
        var buffer = '';
        var i, n;
        for (i = 0, n = chars.length; i < n; i += 3) {
            var b1 = chars.charCodeAt(i) & 0xFF;
            var b2 = chars.charCodeAt(i + 1) & 0xFF;
            var b3 = chars.charCodeAt(i + 2) & 0xFF;
            var d1 = b1 >> 2, d2 = ((b1 & 3) << 4) | (b2 >> 4);
            var d3 = i + 1 < n ? ((b2 & 0xF) << 2) | (b3 >> 6) : 64;
            var d4 = i + 2 < n ? (b3 & 0x3F) : 64;
            buffer += (digits.charAt(d1) + digits.charAt(d2) +
                digits.charAt(d3) + digits.charAt(d4));
        }
        return buffer;
    };
})();

// window.atob (base64 encode function) ?
(function checkWindowAtobCompatibility() {
    if ('atob' in window)
        return;

    // https://github.com/davidchambers/Base64.js
    var digits =
        'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
    window.atob = function (input) {
        input = input.replace(/=+$/, '');
        if (input.length % 4 == 1) throw new Error('bad atob input');
        for (
            // initialize result and counters
            var bc = 0, bs, buffer, idx = 0, output = '';
            // get next character
            buffer = input.charAt(idx++);
            // character found in table?
            // initialize bit storage and add its ascii value
            ~buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer,
                // and if not first of each 4 characters,
                // convert the first 8 bits to one ascii character
                bc++ % 4) ? output += String.fromCharCode(255 & bs >> (-2 * bc & 6)) : 0
            ) {
            // try to find character in table (0-63, not found => -1)
            buffer = digits.indexOf(buffer);
        }
        return output;
    };
})();

// Function.prototype.bind ?
(function checkFunctionPrototypeBindCompatibility() {
    if (typeof Function.prototype.bind !== 'undefined')
        return;

    Function.prototype.bind = function functionPrototypeBind(obj) {
        var fn = this, headArgs = Array.prototype.slice.call(arguments, 1);
        var bound = function functionPrototypeBindBound() {
            var args = Array.prototype.concat.apply(headArgs, arguments);
            return fn.apply(obj, args);
        };
        return bound;
    };
})();

// HTMLElement dataset property
(function checkDatasetProperty() {
    var div = document.createElement('div');
    if ('dataset' in div)
        return; // dataset property exists

    Object.defineProperty(HTMLElement.prototype, 'dataset', {
        get: function () {
            if (this._dataset)
                return this._dataset;

            var dataset = {};
            for (var j = 0, jj = this.attributes.length; j < jj; j++) {
                var attribute = this.attributes[j];
                if (attribute.name.substring(0, 5) != 'data-')
                    continue;
                var key = attribute.name.substring(5).replace(/\-([a-z])/g,
                    function (all, ch) {
                        return ch.toUpperCase();
                    });
                dataset[key] = attribute.value;
            }

            Object.defineProperty(this, '_dataset', {
                value: dataset,
                writable: false,
                enumerable: false
            });
            return dataset;
        },
        enumerable: true
    });
})();

// HTMLElement classList property
(function checkClassListProperty() {
    var div = document.createElement('div');
    if ('classList' in div)
        return; // classList property exists

    function changeList(element, itemName, add, remove) {
        var s = element.className || '';
        var list = s.split(/\s+/g);
        if (list[0] === '') list.shift();
        var index = list.indexOf(itemName);
        if (index < 0 && add)
            list.push(itemName);
        if (index >= 0 && remove)
            list.splice(index, 1);
        element.className = list.join(' ');
        return (index >= 0);
    }

    var classListPrototype = {
        add: function (name) {
            changeList(this.element, name, true, false);
        },
        contains: function (name) {
            return changeList(this.element, name, false, false);
        },
        remove: function (name) {
            changeList(this.element, name, false, true);
        },
        toggle: function (name) {
            changeList(this.element, name, true, true);
        }
    };

    Object.defineProperty(HTMLElement.prototype, 'classList', {
        get: function () {
            if (this._classList)
                return this._classList;

            var classList = Object.create(classListPrototype, {
                element: {
                    value: this,
                    writable: false,
                    enumerable: true
                }
            });
            Object.defineProperty(this, '_classList', {
                value: classList,
                writable: false,
                enumerable: false
            });
            return classList;
        },
        enumerable: true
    });
})();

// Check console compatibility
(function checkConsoleCompatibility() {
    if (!('console' in window)) {
        window.console = {
            log: function () {
            },
            error: function () {
            },
            warn: function () {
            }
        };
    } else if (!('bind' in console.log)) {
        // native functions in IE9 might not have bind
        console.log = (function (fn) {
            return function (msg) {
                return fn(msg);
            };
        })(console.log);
        console.error = (function (fn) {
            return function (msg) {
                return fn(msg);
            };
        })(console.error);
        console.warn = (function (fn) {
            return function (msg) {
                return fn(msg);
            };
        })(console.warn);
    }
})();

// Check onclick compatibility in Opera
(function checkOnClickCompatibility() {
    // workaround for reported Opera bug DSK-354448:
    // onclick fires on disabled buttons with opaque content
    function ignoreIfTargetDisabled(event) {
        if (isDisabled(event.target)) {
            event.stopPropagation();
        }
    }

    function isDisabled(node) {
        return node.disabled || (node.parentNode && isDisabled(node.parentNode));
    }

    if (navigator.userAgent.indexOf('Opera') != -1) {
        // use browser detection since we cannot feature-check this bug
        document.addEventListener('click', ignoreIfTargetDisabled, true);
    }
})();

// Checks if possible to use URL.createObjectURL()
(function checkOnBlobSupport() {
    // sometimes IE loosing the data created with createObjectURL(), see #3977
    if (navigator.userAgent.indexOf('Trident') >= 0) {
        PDFJS.disableCreateObjectURL = true;
    }
})();

// Checks if navigator.language is supported
(function checkNavigatorLanguage() {
    if ('language' in navigator)
        return;
    Object.defineProperty(navigator, 'language', {
        get: function navigatorLanguage() {
            var language = navigator.userLanguage || 'en-US';
            return language.substring(0, 2).toLowerCase() +
                language.substring(2).toUpperCase();
        },
        enumerable: true
    });
})();

(function checkRangeRequests() {
    // Safari has issues with cached range requests see:
    // https://github.com/mozilla/pdf.js/issues/3260
    // Last tested with version 6.0.4.
    var isSafari = Object.prototype.toString.call(
        window.HTMLElement).indexOf('Constructor') > 0;

    // Older versions of Android (pre 3.0) has issues with range requests, see:
    // https://github.com/mozilla/pdf.js/issues/3381.
    // Make sure that we only match webkit-based Android browsers,
    // since Firefox/Fennec works as expected.
    var regex = /Android\s[0-2][^\d]/;
    var isOldAndroid = regex.test(navigator.userAgent);

    if (isSafari || isOldAndroid) {
        PDFJS.disableRange = true;
    }
})();

// Check if the browser supports manipulation of the history.
(function checkHistoryManipulation() {
    if (!window.history.pushState) {
        PDFJS.disableHistory = true;
    }
})();
